Drinks made from the dried roots of the kava shrub have been used in the South Pacific for hundreds of years and in Europe since the 1700s. The drink is reported to have pleasant mild effects similar to those of alcoholic drinks. Kava use has spread in Aboriginal communities in Australia over the last 20 years, where it is often combined with alcohol. In Fiji, kava is still used during welcome and religious ceremonies.

Studies report that kava may help treat anxiety in as few as 1-2 doses, with continued improvements over 1-4 weeks. Early evidence suggests that kava may be as effective as antianxiety drugs like benzodiazepines. Kava preparations were widely used in Europe and the United States to relieve anxiety but have been withdrawn in several European markets and Canada due to safety concerns.

There is promising evidence supporting the use of kava in improving cognition, depression, and hot flashes. More research is needed to make firm conclusions.

Kava has been used as a treatment for insomnia. However, many experts believe that kava may lack effectiveness for this purpose. Chronic or heavy use of kava has been linked to changes in the nervous system or skin, as well as high blood pressure in the lung arteries.

There is widespread concern that kava may be harmful to the liver. More than 30 cases of liver damage have been reported in Europe, including liver swelling, inflammation, scarring, dysfunction, and failure, as well as some reports of death. However, some experts maintain that kava is safe in most people when used in recommended doses. It is unclear what dose or length of use may be lead to liver damage. This remains an area of controversy.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Many studies report that kava is moderately effective for relieving anxiety. Kava has been found to promote significant improvement of anxiety symptoms. Early evidence suggests that kava may be as effective as antianxiety drugs like benzodiazepines. Kava's effects may be similar to the prescription drug buspirone (Buspar®). The German expert panel Commission E has approved kava for anxiety, stress, and restlessness.

A

There are conflicting results on the effectiveness of kava for cognitive aspects such as memory, attention, and reaction time. It has been suggested that kava may not have sedative effects at recommended doses, which may be an advantage over some drugs. There is early evidence that kava may improve mental performance. More research is needed before firm conclusions can be made.

C

There is some evidence that kava may help relieve depression. Kava has been used in combination with St. John's wort in people with depression and anxiety. Further research is needed in this area.

C

Early study suggests that kava may significantly improve hot flashes, compared to placebo. High-quality research is needed before conclusions can be made.

C

There have been some reports that kava may have sedative effects. However, there is conflicting evidence. Some studies have found a lack of sedation with kava use. Early research reported that kava lacked significant effects in people with insomnia. More research is needed to determine whether kava is effective for this condition.

C

Early research suggests that kava and valerian may improve health by reducing stress and insomnia caused by stress. More research is needed to confirm these results.

C

It is unclear whether kava is safe or effective for use in people with Parkinson's disease. Kava may increase periods of reduced mobility in people taking levodopa and may cause a semicomatose state when levodopa is taken with alprazolam. More research is needed in this area to make a firm conclusion.

D

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

Kava extract taken by mouth as 300 milligrams daily in three divided doses has been reported as effective and well tolerated. Typical doses range from 50 to 280 milligrams of kava lactones daily as a single dose or divided doses.

To treat anxiety, doses range from 50 to 400 milligrams daily. A dose of 100 milligrams has been taken by mouth three times daily. A dose of 50 milligrams of WS 1490 has been taken by mouth three times daily for up to four weeks. Two 50-milligram capsules have been taken by mouth the evening before surgery, followed by two 50-milligram capsules taken by mouth 60 minutes before surgery. A dose of 400 milligrams of Kava-Kava LI150 has been taken by mouth daily. A capsule containing 150 milligrams of kava kava rootstock (Kavosporal® forte) has been taken by mouth for seven days. Five tablets, each containing 50 milligrams of kavalactones, have been taken by mouth in three divided doses (two in the morning, two in the afternoon, and one in the evening) daily for one week. A dose of 400 milligrams of kava has been taken by mouth daily for eight weeks. A one-time dose tablet of 60 milligrams of kavalactones has been taken by mouth. Doses of 50-7,980 milligrams of dry kava extract have been taken by mouth daily for 3-24 weeks. A dose of 280 milligrams of kava has been taken by mouth daily for four weeks. Kava extract-pure® containing 140-280 milligrams of kavapyrones has been taken by mouth daily for four weeks. P. methysticum LI 50 extract has been taken by mouth daily for eight weeks.

To improve cognition, a one-time dose of three kava tablets (each containing 60 milligrams of kavalactones) has been taken by mouth. The following doses have been taken by mouth: 300-600 milligrams of kava extract, 450 milligrams per liter of kawain and dihydrokawain, 30 grams of kava powder, one gram of kava per kilogram, and 200-600 milligrams of synthetic kava. Doses of 100-440 grams of kava powder have been taken by mouth weekly.

To treat depression, five tablets (each containing 50 milligrams of kavalactones) have been taken by mouth in three divided doses (two in the morning, two in the afternoon, and one in the evening) daily for one week.

To improve mood, a single dose of 300 milligrams of kava extract has been taken by mouth.

To treat hot flashes, 100 milligrams of kava has been taken by mouth daily.

To treat insomnia, kava special extract WS 1490 has been taken by mouth in daily doses of 200 milligrams. A dose of 120 milligrams of kava has been taken by mouth daily for six weeks. One soft gel capsule containing 100 milligrams of kavalactones has been taken by mouth three times daily.

Children (younger than 18 years)

There is no proven safe or effective dose for kava in children.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

Avoid in people with known allergy or sensitivity to kava (Piper methysticum), kavapyrones, or any of its parts.

Kava is possibly safe when taken by mouth in recommended doses over short periods of time (fewer than 1-2 months). In general, kava has had a history of relatively safe use. However, there have been reports of severe liver problems or death, and the U.S. Food and Drug Administration (FDA) has issued warnings about kava use. Kava should be used only under the supervision of a qualified healthcare professional and should never be used above recommended doses.

Kava may increase the risk of bleeding. Caution is advised in people with bleeding disorders or those taking drugs that may increase the risk of bleeding. Dosing adjustments may be necessary.

Kava may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system.

Use cautiously in pregnant or breastfeeding women.

Use cautiously in people who have depression, heart disorders (including abnormal heart rhythms or high blood pressure in lung arteries), and rhabdomyolysis (breakdown of muscle fibers).

Use cautiously in people who are taking antidepressants, bee pollen, black cohosh, nettle, and valerian.

Avoid in people with known allergy or sensitivity to kava (Piper methysticum), kavapyrones, or any of its parts.

Drowsiness or sedation may occur. Avoid if driving or operating heavy machinery.

Avoid in people who have chronic lung disease, liver damage or disease, Parkinson's disease, or a history of movement disorders.

Avoid in people who plan to undergo surgery in 2-3 weeks.

Avoid using with agents that harm the liver (including acetaminophen, HMG CoA reductase inhibitors, isoniazid, and methotraxate), and other central nervous system (CNS) depressants, such as alcohol or benzodiazepines.

Avoid using for longer than 1-2 months or in doses greater than recommended (more than 300 milligrams daily).

Pregnancy & Breastfeeding

There is a lack of scientific evidence on the use of kava during pregnancy or breastfeeding.

Kava may increase the risk of bleeding when taken with drugs that increase the risk of bleeding. Some examples include aspirin, anticoagulants (blood thinners) such as warfarin (Coumadin®) or heparin, antiplatelet drugs such as clopidogrel (Plavix®), and nonsteroidal anti-inflammatory drugs such as ibuprofen (Motrin®, Advil®) or naproxen (Naprosyn®, Aleve®).

Kava may interfere with the way the body processes certain drugs using the liver's cytochrome P450 enzyme system. As a result, the levels of these drugs may be increased in the blood and may cause increased effects or potentially serious adverse reactions. People using any medications should check the package insert and speak with a qualified healthcare professional, including a pharmacist, about possible interactions.

Kava may increase the sedative effects caused by some drugs. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants (including monoamine oxidase inhibitors [MAOIs] and selective serotonin reuptake inhibitors [SSRIs]), and alcohol. Caution is advised while driving or operating machinery.

Kava may increase the risk of bleeding when taken with herbs and supplements that are believed to increase the risk of bleeding. Multiple cases of bleeding have been reported with the use of Ginkgo biloba, and fewer cases with garlic and saw palmetto. Numerous other agents may theoretically increase the risk of bleeding, although this has not been proven in most cases.

Kava may interfere with the way the body processes certain herbs or supplements using the liver's cytochrome P450 enzyme system. As a result, the levels of other herbs or supplements may become too high in the blood. It may also alter the effects that other herbs or supplements possibly have on the P450 system.

Kava may increase the sedative effects caused by some herbs or supplements, including those with effects similar to those of central nervous system depressants, monoamine oxidase inhibitors (MAOIs), and selective serotonin reuptake inhibitors (SSRIs).

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.